1. Field of the Invention
Exemplary embodiments of the present invention relate to a user recognition apparatus and method; and, particularly, to an apparatus and method for recognizing a user using an infrared-light camera and a visible-light camera.
2. Description of Related Art
A stereo camera is used for a method of acquiring depth information by processing two images acquired from two cameras. The method of acquiring depth information using two images may include a method of extracting depth information using a pixel distance between the two images. Recently, a method of extracting depth information by applying an optical flow method to two images has emerged.
The method of extracting depth information using an optical flow method cannot acquire more precise depth information than the method of extracting depth information using a pixel distance, but requires a simple initial setting and does not require a correction operation for distortion caused by a camera lens. Therefore, the depth information acquired by the method of extracting depth information using an optical flow method is mainly used in a motion recognition area which does not require precise depth information.
In the method of acquiring depth information using an optical flow method, when the size of an image is doubled side to side, the total number of pixels increases by the square of the image size, and an operation amount of the optical flow method corresponding to the image increases by the square. Although depth information is not required for motion recognition, information for motion recognition enables more precise motion recognition when including information on a larger number of pixels. Therefore, two images acquired through the stereo camera enable precise motion recognition, as the size of the two images increases.
However, with the increase of the image size, the operation amount of the optical flow method also significantly increases. Therefore, although the precision increases, the operation speed significantly decreases. In order to solve such a problem, the background of an infrared-light image acquired by an infrared-light camera may be removed to increase the speed. When the infrared-light image, of which the background is removed, is applied, it is possible to acquire depth information more quickly than when an optical flow method corresponding to the entire infrared-light image is applied.
However, when the infrared-light camera is used to collect a specific light range of data, it is possible to acquire data which are not sensitive to light dispersion or light intensity change. However, the number of color channels acquired from an image decreases, and it is difficult to apply an algorithm capable of processing an image using color values of the image.